Electric-current rectifier



July 31, 1928'. 1,678,826

s. RUBEN ELECTRIC CURRENT RECTIFIER Filed April 26, 1927 1 (rill/[1m INVENTOR.

BY 2 I 7 I f I a ATTORNEYS.

Patented July 31, 1928 UNITED STATES PATENT oFncE.

SAMUEL RUBEN, OF NEW YoRx, N. Y., ASSIGNOR To RUBEN "RECTIFIER COBPORA- TION, E ENGLEWOOD, NEW JERSEY, A CORPORATION or DELAWARE.

- LEcrRIc-cURRE r REcrIEIER.

Application filed April 26, 1927:. Serial No. 186,606.

This invention relates to electric current rectifiers and the like, which employ asymmetric couples of the dry surface-contact variety.

Rectifiers of this variety are known, which are characterized by the use of a bod of relatively electropositive material, employed as one electrode element, disposed in electrical contact with a body of relatively electronegative material employed as the other electrode element; there being an intervening film having inverse current-blockingproperties. Such rec-tifiers depend for their operation upon the resistance and current-blocking characteristics of the film, which forms as the result of electrochemical action. Rectifiers depending on these characteristics known to the prior art, have been 10W in efiiciency and limited in their application to small current, because of improper conditions for film formation and maintenance, and become substantially inoperative after short periods of use.

This invention has for its object generally to provide an improved device of the character specified, which is efficient, economical and readily manufactured.

More specifically an object of the invention is to provide an asymmetric couple in which the electronegative electrode element is so formed that there is substantially a minimum tendency to the formation of resistance material as a reaction product at the contacting surfaces when passing current, and so arranged that the electrode elements will adjust themselves under varying operating conditions to have substantially maximum contacting area.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

' The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts, which will be exemplified in the constructions hereinafter set forth and the scope of the application of which will be indicated in the claims. j

For a fuller understanding of the nature and objects of the invention, reference. should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure 1 shows diagrammatically 9. rectifyin device constructed in accordance with t emvention;

F1g. 2 1s a v1ew 1n cross-sectlonshowing the' electrode elements here employed in assembled arrangement; and

Fi 3 is a cross-sectional view, similar to Fig. 2, showing a modified arrangement of electrode elements.

Referring now to the drawing, and particularly to Fig. 2, 1O denotes a cup or receptacle having upturned sides, which is made of suitable conducting material; for example, copper, brass or steel. -In this cup is disposed a layer of material 11 here employed as the electropositve electrode element.

The electronegative electrode element is shown as a plate member, or disc 12, disposed in the cup in co-operative contact with the -material 11. The arrangement of the electrode elements is such as to permit assembly by means of a clamping bolt. To

this end on 10, layer 11 and disc 12 are perforated an have an insulating tube 13 passing therethrough. In order also that the electrical relation of the electrode elements be not disturbed at their outer edge, an insulating-collar 14 is inserted between the upstanding rim of the cup 10 and the edge of the disc 12. 1

The electrode elements thus assembled in cup 10 comprise an asymmetric couple which aifords a convenient unit from which to build up a rectifying device of any desired In the arrangement shown in Fig. the

couples are arranged in two groups of two couples each, the groups being inverted with respect to each other and disposed conductively against the central conducting terminal plate 15. The couples in turn are separated by interposed conducting terminal-plates 16, there being conducting terminal-plates 17 at the ends of the assembly which are held together under compression by means of a conducting clamping-bolt 18, which has spring-washers 19 interposed between its heads and the end-plates 17. By this arrangement it is seen that the four couples here employed comprise the arms of a Wheatstone bridge, of which the terminals provided at 15 and 18 comprise one diagonal of the bridge circuit, and are adapted to serve terminals for output circuit of the rectifying device, here shown as the conductors 20 and 21, leading to the terminals of a direct-current consumingdevice, here symbolically indicated by the signs and The terminal-plates 16- disposed intermediately of the'groups, serve as terminals for the other diagonal of the bridge circuit, and

as conductors-22 and 23, leading from the low tension side of a suitable step-down connected to an original source 25 of'alternating current for example, a commercial 60-cycle, llO-volt, A.,C.-suply.

By the arrangement shown, when the con-' ductor 22,.ha's-a plus polarity, the electronegative electrode element in the cup 10 adjacent the terminal-plate 16, to which the con- I rial; this material may be of any suitable kind, for example, molded bakelite. 'Inth1s.

form of the device, the electronegative electrode element- 32 is in disc-form and 1s placed in the bottom of cup 30 and has. a-;

layer of powdered electropositive. material 1 31 disposed thereon. An insulating tube 33 passes throughthe rectifying elements and .has disposed about it a conducting element 34, such as a plate ,of copper, for applying pressure to the "powdered material under it; These elements are heldin operative assem.-

blyvby the bolt and nut shown at 35 aspasswf ing through the insulating tube 33 and ap plying pressure, when drawn -up,-".through' j ,tl 1e spring washer" 36 to the disc :34 to the rectifying elements beneath- A conducting terminal for the electronegative electrode element is provided which preferablypene trates the insulatingcup. This; terminal is 5 here shown as a screw 37 secured cup 30 and in conducting. contact with the electro-' negative electrode element.

This modified form of the inventio n'oper ates in the same manner asthat first described above; the rectifying cou'plebeing connected vin a circuit, either as a single cell or as a unit having a plurality oi-cells, by

connecting conductors to the terminal 37 and to the bolt 35. The'cup 30, however, is here seen to provide a convenient alternative con-v are employed for making connections to the alternating-currentinput circuit, here shown transformer 24, which is here shown as,

struction for the cup 10 whereby insulating material is employed instead of conducting material.

The electropositive electrode element hereemployed is a layer of metallic material in powder form of substantially any relatively suit-able, but highly chemically :active," elec tropositive element, for example, aluminum, boron, calcium, ma e'sium and .zinc, as taught in my co-pen g application, Serial No. 69,215, filed November 16, 1925.

or derivative from, a highly electronegati've chemical element,'Which is adapted to react electrochemically at the contactingsurface with the elect'ropositive material to form an inverse current-blocln'ng film. Metallic compounds with the elements, of the sixth group in the periodic'table are suitable compounds from which to provide the material I for the electronegative electrode element, as

, also'set forth in my co-pen'ding application above referred to. In this prior application it was pointed out as desirable to employ a metallic alloy as the basic metallic material material is thereby provided having sufforming properties to the asymmetric couple;

A reaction product is electrochemically formed at the contacting surfaces of the elecoo l to be compounded with the chemical ele: ments of the sixthgroup, since a body of 'ficient resistance to impart inherent 'filmtrode elements, inaddition to the inverse curful life ofthecouple. The rate of the formation of this reaction product is .rou hly inversely proportional to the density 0 the elect-ronegative electrode ,element As this element is generally a compound in. crystal.

form, this density is herein referred to as the -crystalydensity; It has been ascer -tain'ed that the crystal density and mechanical strength and rigidityof the electronega-' ,tive electrode element may be increased to- ,rent-blocking film which gradually increases in resistance, thereby cutting down the use 11-50 v gether by the addition 'of further alloy material which is metallic in nature, imparting hardness but does not decrease the electro- The material suitable for this purpose consists of the refractory metals of the sixth periodic group, sometimes referred to as.

subgroup B thereof; namely, the metals of these latter metals is obtainable commerciallyin oxide'form, which oxides have-been negative character oi the electrode element.

chromium, molybdenum and tungsten. Each ascertained to be suitable forms to be added.

to the basic material of theelectrode element. These elements may be taken 1 in; amounts up to substantially 20% by weight of the total mass of the electronegative electrode when accomplishing the object of the invention.

The following is an example of suitable components for the electronegative electrode 75, The electronegative electrode element is a body of material which is a compound with,

element, which reacts well with an electropositive electrode element of powdered magnesium:

These materials are fused togethcrat a temperature of substantially 1300 C, and are cast into discs or small plates.

In order to insure maximum density, the cast plates, while still plastic, are worked by mechanically rolling the same until reduced from one-half to one-third of their original thickness. This working preferably takes place at a temperature of about 600 C. i

' When electronegative electrode elements are thus produced, they have substantial maximum density for the material employed, and when assembled in contact .withthe powdered electropositive electrode element in the cup 10, together they form an asymmetric couple that is highly resistant to the formation ofany reaction-resistance prodnot at their contacting surfaces. Such couples, when assembled, as indicated in Fig. 1, have pressure applied to them as-set forth in my (to-pending application, Serial No. 38,781, filed June 20, 1925, in order to prevent the inverse current-blocking film from being disrupted by the forces of electrostatic repulsion that operate at the contactmg surfaces when rectifying current passes.

' By employing an electropositive electrode element 1n powder form, it is seen that it is adapted to adjust itself for intimate contact with the surface of the electronegative electrode element so that there is substantially a maximum of conducting area under all conditions of operation, thereby insuring that the device may be operated at substantially maximum current densities without danger of destroying the inverse currentblocking film by overheating at any point in the contacting surface. The couple thus provided consequently has high stabilit and is adapted to give a relatively longli e under relatively severe operating conditions.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description, or shown in the accompanying drawing, shall be interpreted as illustrative and not in a limiting sense.

'Having described my invention, what I claim as new and desire to secure by Letters Patent is: 1

1. In dry surface-contact rectifying devices and the like, an asymmetric couple having an electronegative electrode element comperiodic group,

mum crystal-density,

having substantially maxian electropositlve electrode element comprislng highly electropositive metallic material in powder form, and means for retainmg sald electrode elements 111 contact under pressure sufiicient to prevent the disruption of the inverse current blocking film which forms at the contacting surfaces of said electrodes. 2. In dry surface-contact rectifying devices and the like, an asymmetric couple having an electronegative electrode element comprising a metallic compound of the sixth periodic group, mum crystal density, and which is relatively highly resistant to the formation of reaction resistance products, an electropositive elec trode element comprismg highly electropositive metallic material in powder form, a

containing cup adapted to hold said electropositive electrode element in co-operative contact with said electronegative electrode element, and means for retaining said electrode elements in contact vunder pressure sufficient to prevent the disruption of the inverse current blocking film which forms at the contacting surfaces of said electrodes.

3. In dry surface-contact rectifying devices and the like, an asymmetric couple having comprising a compound ofv the sixth periodic group with an alloy having a relatively having substantially maxian electronegative electrode element highly-conducting metallic component, a

second metallic comptpnent adapted to increase the resistance thereof and to increase the. density, durability and resistance to the formation, electrochemically, of reactionresistance products on the surface thereof, an electropositive electrode element comprising highly electropositive metallic material [in powder form, a containing cup for holding the latter in co-operative contact with the electronegative electrode element, and means for retaining said electrode elements in contact under pressure sufficient to prevent the disruption of the inverse currentblocking film, which forms at the contacting surfaces of said electrodes. 1

4. In dry surface-contact rectifying devices and the like, an asymmetric couple havingan electronegative electrode element comprising a compound of the sixth periodic group with an alloy containing copper and a relatively highly refractory electronegative metallic element, adapted to increase the crystal density of said electrode element and to render the same resistant to the forn'iation of reaction resistance products, an electropositive electrode element comprising highly electropositive metallic material in powder form, a containing cup adapted to contain said electrode elements in contact, means for insulating the edges of said electrode elements within said cup, and means for re- ,prising a metallic compound of the sixth taining said electrode elements in contact under pressure suflicient to preventv the disruptionof the inverse current-blocking film which forms at the contacting surfacesof said electrodes;

vices .and the like, an asymmetric couple havprising a compound of the sixth periodic group with an alloy containing copper, zinc and chromium, taken in proportions adapt ed to imp-art high crystal; density and to render the samerelatively highly resistant to the electrochemical. formation of reaction resistance products on the surface thereof,v an electropos'itive electrode element comprising metallic magnesium in powder form; a containing cup adaptedto contain said powder material and to support said electronegative electrode element in contact with the electropositive electrode element, insulating means inserted in said cup and adapted to insulate the edges of said electrode ele-" -men-ts, and means for retaining said electrode elements in contact under pressure sufvficient to prevent the disruption of the in-' verse current-blocking film which forms at;

.thecontacting surfaces of said electrodes. 6. In dry surfacecontact rectifying devices and the like, an asymmetric couple hav 'ing' electronegative electrode elements comprising a compound of the sixth periodic group with an alloy containing copper, zincand chromium takem in proportions adapted to impart high crystal'density and to render the same relatively highly resistant to the electrochemical formation of reaction resistance products on the surface thereof, an

' electropositive electrode element comprising highly electropositive metallic material in v powdered form, acontaining cup adapted. to

' contain said electrode elements disposed in operative contact, means for insulating the edges of said electrode elements, a closure for said cup, and resilient means bearing on said closure adapted to retain said electrodeelements in contactunder pressure suf- -ficienttog prevent the disruption of the inversecurrent-blocking" film which forms at v t the contactingsurfaces of said electredes. "1 5. In dry surface-contact rectifying d'e- 7.111 dry surface contact rectifying devices and the like, an asymmetric couple havingan electronegative electrode element coming' electione'gative electrode elements comgroup,.with an alloy containing copper, zinc and chromium taken in proportions adapted to impart high crystal density and to render the same relatively highly resistant to the electrochemical formation of reaction resistelements disposed in operative contact.', means for insulating the edges of said electrode elements, a closure, for saidcup, and resilient means bearingon said closure adapted .to

retain said electrode'elements in contact unprising a'eompound of-the sixth periodic der pressure suificient to prevent thedisrup tion of the "inverse current-blocking film &

'which forms at the contacting surfacesof said electrodes.

7 8. In' dry surface contactrectifying devices andthe like, an asymmetric couple com- .prising a pair of electrode elements,- one in- 75- cup adapted ,contain: said electrodefele- -ments disposed -in;operativ e contact, insulat npowdered form, the other in solid form, a

mg means associated with said 'gcup' and adapted to maintain the edges of said ele-, ments in proper insulated relation, means censisting-of a freely-moving member for- ;closing said cup, and clamping means adaptedtobear on said closing means arranged to maintain said'electrode elements incontact under pressure suflicient to prevent a disruption of the inverse current-blocking film which forms at the contacting surfaces of said electrodes.

In testimony whereof I aflix my signature. SAMUEL RUBEN, 

